include an option of changing mobs texture in texture creator please
you could create a 5th division of texture creator (blocks, itens, paintings, armor ) . it would be the mob one. then it would appear a list of the mobs and you change head, body ... for humanoid mobs (zombie, husk. ..) it would be able to use your own projects on skin creator.
there used to be files like that in the texture packs but you had to get a pixel editor to do it but they removed those files